It's not easy to find the right items for a versatile champion like Wukong. The build I show you is just the most flexible build.

Jungle start
Spirit Stone has good upgrades like Spirit of the Elder Lizard and Spirit of the Ancient Golem. But: An early The Brutalizer will help you out more in the mid game which is Wukongs time in the game to shine. Different from Kha'Zix, Wukong doesn't need any mana or mana regen, even in the jungle. And he doesn't need the extra damage from Spirit Stone to be fast enough in the jungle. That's why I go for Doran's Blade.


Boot choices
Boots on Wukong are very essential and you should get Boots very early.
Enchantment: Alacrity and Enchantment: Furor are very good upgrades and will help Wukong out with his ultimate since many popular 3v3 champions can escape it easily.
Mercury's Treads are normally the choice against a team that can stun or interfere your movement with snares, roots and all the other things.
Ionian Boots of Lucidity are nice. But since they don't give you any tanky stats I generally don't build them on a tanky Wukong who is oftentimes the only tank in the team.
Ninja Tabis are a very good choice since they block auto attack damage. In combination with a Doran's Shield you're tanky early game against most non-assassin ADs. Doran's Shield is useless later though when you block 8 damage from a 400 damage crit.
Boots of Swiftness can work against for example Teemo or Singed who simply run away from your ult.
But don't take my word for it, just build Sorcerer's Shoes. Oh Mobility Boots don't work either since your stealth duration is kinda short.

Items
Tanky armor items can be Sunfire Aegis, Randuin's Omen and Iceborn Gauntlet (frozen fist). Sunfire Aegis helps you out with jungling and gives a slight bonus for your ultimate. Randuin's Omen is such an awesome item, the slow is the best stat of it and a huge bonus for teamfights and your ultimate, very strong in 3v3, but it doesn't help you in the jungle. Iceborn Gauntlet is amazing because of the huge armor it provides, if you decide for it, get the Sheen early, the mana is useful for spamming the jungle. The cooldown reduction and slow make it one of the best items on Wukong and other champions in Season 3, the disadvantage is simply that you trade health for mana.
Black Cleaver is pretty standart on Wukong because of its huge physical AoE damage, cooldown reduction and the other cool stats that an AD bruiser needs. Youmuu's Ghostblade is also really good, especially for speeding up your movement speed while you ult. It gives flat armor penetration instead of percentage ArPen, but it doesn't fit into the standart build better than Black Cleaver, you would buy Youmuu's Ghostblade with something like Blade of the Ruined King but auto attack Wukong is a different story and not what this guide is about.
Lifesteal is really core in the jungle, that's why you want to get the Vampiric Scepter early. Good upgrades are the listed Ravenous Hydra because of the AoE damage and flat AD, but also Grez's Spectral Lantern is a good jungle item, gives vision and upgrades into a more powerful AD item.
Last Whisper is pretty standard on every AD carry or caster when enemies build much armor, on Wukong it's very good because with Black Cleaver and Crushing Blow you will deal almost true damage to a single enemy, this also works for tanks. It's like building a Void Staff on Xerath which is almost core.
Mercurial Scimitar is very expensive and a situational item, but it gives much. 60 AD, 45 MR, an active that is stronger than Cleanse and movement speed for your ultimate make it one of the best possible items on Wukong. A good magic resistance item is also the new Spirit Visage which incredibly overpowered at the moment and has probably the best building path of any item in the game. It also grants HP and CDR which is essential on Wukong. Maw of Malmortius is really good, too. Its passives sync very well with each other and your ultimate.
Frozen Mallet is not my style. It costs too much right now, the Phage changes at 3.11 will not affect Frozen Mallet except for its build path. It will cost less and be useful for tanks as an HP item on 3v3.
Trinity Force is better on attack speed Wukong than caster Wukong and also super expensive, it will get better with the phage changes in 3.11. It will get a reworked passive like Phage that will grant movement speed, and it will also grant 30 armor which is pretty much while its cost will get reduced.