Jungle Vayne is now one of the most powerfull champs in the League.
Below you will see why.
Enjoy.

As you propably know the new Devourer makes your champion an unstoppable killing machine if its based on on hit effects such as critical strikes, Cho´s "E" or Aatroxes "W"... or Vayne "Q" with critical strike... or "W".Frankly even her ult which is basicly a huge bonus of attack damage takes part in it `cause of great improvment of critical strikes damage.

As the most Vayne jungle players will propably focus on building possibly biggest attack speed and critical strike to make her auto attack faster and more lethal, I´ll focus on a pure utility. You know going like straight agressive full adc build will be effective unless ure fighting champ who`s not Rammus... or Malp.. or pretty any other tank with hard armour and the way to move fast. I mean of course Vayne pretty good against tanks especially with Devourer which makes her deal more true dmg, BUT it may be not enough and honestly it usually IS NOT enough. That`s why I made this build.
My point is to minimalize the risk WITHOUT loosing the potential dmg, but making it more differential. As the Devourer makes your charakter deal an extra MAGIC DMG and SO IS THE STATTIK SHIV your going to deal a huge amount of ALL KNOWN in League dmg. You will deal up to ~560magical dmg(Doubled Devourer[~60]and doubled critical strike[with IE]Stattik Shiv[~500]) propably every forth autoattack. This makes you amazingly unpredictible for your opponents.

Here you have a couple of options but here`s mine:
-SEALS: As u are jungling with a low hp and armour champion you have to become a little bit more tanky that`s why I recommend HP Seals in combination with Armour Seals and GLYPHS
-MARKS: As u are dealing both kinds of dmg that actually needs a penetration I recommend a Hybrid Penetration Marks with a little of AD.
-GLYPHS:look above
-QUINTS:For Quints I recommend the same solution as for Marks, but as there are more options u could try sth wth movement speed or other stuff.

Here`s the main part. Like I`ve already wrote I made this build a little bit different then the usual pure ADC one. The reason is simple: utility.
Without doubt Vayne is one of the most mobile ranged champions which is wonderfull when ure covered by some sort of support. But as ure a jungler now your survability is only up to you.
That`s why i`ve decided to create that build.
First of all you have to build an jungling item that you has to enchant into Devourer later.
I recommend the Skirmisher`s Sabre `cause of nice burst of damage at the beginnig of the game when ure not so strong. However if u do not feel confident in the jungle u can always buy the Ranger`s Trialblazer.
Then you have to buy Berserker`s Gravers `cause of the obvious reasons. For an enchantment the best will be Fury `cause it fits the other items if that build.
For the third item you have to build the Stattik Shiv because of the reasons I`ve mentioned in "What is not usual about that build" part. You may be sceptic but it`s essential part.
The fourth item depends on how well you`re getting along. If you`re as wonderfull as you should be playing this awesome champ and you have a lot of gold to spend you should concider bouying IE for a huge burst of damage. Otherwise you can build both BotRK and Trinity Force depends on your actual needs.
I hope I don`t have to justify the BotRK in that build `cause it`s just pretty essential item for all Vayne builds.
This is not the case with Trinity Force but I`m going to explain right now.
I recommend Trinity Force `cause of this build`s main cause: utility.
Beside fact that Trinity fits Vayne perfectly (It basiclly upgrades her "Q") it grants a nice burst of movement speed that is so crucial in this build.
Let`s sum up:
This build contains basiclly only pros: grants you huge bonus of movement speed(Stattik Shiv,Fury,Trinity and BotRK), amazingly huge damage of all kind(magic from Devourer and Stattik, bonus physical from Trinity and nearly every other item, and even more true `cause of Sabre and Devourer`s effect), a little more HP from the Trinity Force.