Just to clarify, you shouldn't just have a laundry list of items that you buy on Evelynn that you build every game. You should be adjusting your build to the needs of your team, as well as the itemization of the other players in the game and the champions you're playing against.
With that said, there are two Evelynn builds I'd suggest that aren't largely outclassed by other junglers.
The first is what you ordinarily see in the LCS - AD Bruiser. The only set in stone part of the build is SotEL - after that, you'll generally want no more than one completed AD item before you start building tanky. BotRK, Triforce and Maw are probably the most useful standalone items on her, although it's quite common to just build Cutlass or Hexdrinker and leave it at that until you're at full build. If your teammates can provide plenty of damage, it's fine to just build full tank after your jungle item.
Evelynn has slightly more diverse itemization than most tanks if you take this route - Sunfire Cape, Randuin's Omen and Frozen Heart are all defensible choices for primary armor items, while Maw, Banshee's Veil, Locket and Spirit Visage (kinda) are defensible for MR. Warmog's is potentially useful if you're against a primarily burst oriented team that lacks any sort of % hp damage, but it's pretty niche.
The second is AP Evelynn, which is mostly useful if you want to be splitpushing late game. The build basically functions on the premise of stacking the shit out of AP and abusing the ease with which Evelynn can proc Lich Bane to pressure towers extremely well while also being a respectable duelist. Obviously, this build isn't very useful against, say, a Jax or a Kassadin, and suffers somewhat from being used in the jungle - if laners are farming at least decently, it'll be difficult for you as a jungler to maintain income parity with them, which naturally disadvantages you if you're trying to 1v1 the enemy Top/Mid/ADC. So, the usefulness of this build (alongside all splitpushing junglers) is basically inversely proportional to your Elo. Decide if you'll be able to splitpush against the enemy team in champ select if at all possible, and don't try to use this build if you can't.
Also keep in mind that, since the changes to Evelynn's E a few months ago, she suffers pretty badly from hybrid damage. Late game, you'll be more or less useless as a damage source in teamfights, so you really have to be committed to splitting to make this build work.
The crux of the build is Deathcap, Lich Bane and Spectral Wraith. As long as your other items are giving you AP, you're good - build for the game.
