Hi, this is my build for jungling as Sejuani. I've tried this build in both rank and normals and it does fine.

My runes I use are MP Reds, Flat Armor Yellows, Mr/L Blues, and either Flat Health Quints or Movespeed Quints.

Masteries I prefer are 9/21/0 because her early game jungling is quite weak she gets really low sometimes but should not be a problem.

Regrowth Pendant + 1 HP Pot > Philo Stone + Lv1 Boots > Heart of Gold > Giant's Belt > Merc Tread's > Sunfire Cape > Glacial Shroud > Frozen Heart > Banshee's Veil > Abyssal Sceptre or Rylia's Sceptre.

Item I start with is Regrowth pendant + 1 HP Pot, once I clear jungle starting from Blue > Wolves > Wraiths > Golems > Red. Gank if needed after Red or whenever you see a possible kill.

After that I usually return and finish Philo + lvl 1 Boots. Move onto finishing Heart of Gold, then if all is going well continue onto Merc Treads + Sunfire Cape because the cape improves her DPS by ALOT. If you dont believe me try this build. Depending on how the game is going buy the Glacial Shroud if their AD is carrying but buy the Negatron Cloak if AP is carrying. Either way they both go into her items. Finish the Shurelyas after the Sunfire cape usually then make your Frozen Heart when possible. After this Make your Banshee's and either finish off with Abyssal Sceptre or make another Health item such as Rylia's to increase the DPS from Sunfire Cape + your W.

The Summoner Spells I prefer are Ghost + Smite. Reasoning for Ghost is because She has her Q for escapes + chasing and Ghost can keep up with escaping enemies keeping them permaslowed for that kill or just to escape with your Q + Ghost.