The once king of the jungle, Graves, has struggled pretty heavily since arguably Patch 6.21. In 6.21 his [E] Quickdraw was pretty heavily hit, only granting half the amount of resists when using it to kite backwards. Pair that with the removal of being able to prevent the knock-back from [R] with a buffered [E] and the removal of Magic Resist from [E] Quickdraw and Graves has been digging his own grave ever since.
League’s latest patch (8.8) seems to have brought him back to a strong state with the simple addition of base health growth per level and [R] cooldown. While they may seem like small buffs, the extra health when paired with his natural ‘tankiness’ from [E] stacks means you’re going to excel even more where Graves was meant to, dueling.
The new rune system seems to be pretty favorable to Graves as well, allowing you to alter your decisions based on play-style.
Aggro/early-game gank pressure: Electrocute’s massive burst damage is rather easy for Graves to proc with a quick [W]->[Q]->Auto making you a formidable early damage threat and snowballing a lead.
Jungle efficiency and control: Fleet Footwork’s ability to provide jungle sustain means that as Graves you’re almost always going to be topped off at full health while clearing. The extra health gives you the freedom to find smart invades and control the river safely.