Graves is incredibly bursty but has a more unique playstyle compared to a lot of ADCs, since he's much closer range. Cait is a well rounded ADC who specializes in bullying from long range. Cait's playstyle is much slower and tactical, where you just gain small advantages over and over again, slowly choking out your opponent, where Graves gets in your face and blows you up. Graves is more snowbally, and players in lower elos don't really abuse his low range, so he's pretty powerful. Both are fun to play and among my favorite ADCs, but I personally prefer Cait since I like the more strategic gameplay (although it is very fun just to blow people up as Graves). Graves is very snowbally; Cait has fewer weaknesses and fewer outstanding strengths unless she's super far ahead/end game. Another common misconception is that Caitlyn is actually a utility ADC (because of the zone control she offers with her traps, also just being able to chunk a carry before a fight with her ult gives her team a really big advantage), similar to Ashe or Sivir, who just happens to deal a good amount of damage as well.
Other ADCs to consider are MF (her ult destroys teams) and Lucian (very popular right now, he's very well rounded, basically doesn't have a weak point in the game). Ezreal is really popular right now with the resurgence of his blue build. Jinx, Tristana, and Corki are my other favorites.
