I'll elaborate a bit here, if you don't mind:
Like most Eeveelutions, Sylveon suffers from a wide movepool, leaving it with few, weak moves to battle with, most of which are physical, and given Sylveon's low Attack stat must be neglected. The few remaining possibilities are Shadow Ball, Moonblast and Hyper Beam.
Hyper Beam is a big no-no because of the recharge, and it is Normal type. Now, Moonblast is a valid substitute, but for Dazzling Gleam or even Draining Kiss. That is however, your choice, leaving only Shadow Ball to replace Swift. Shadow Ball helps the team in general with a bit of coverage should you happen to need it.
Also, since you mentioned Moon, I am assuming you don't use it competitively, so I refrained from Status Moves like Misty Terrain and the like to help the rest of your team out. In most cases, you don't need a Support Pokemon in game, so I left out moves like Wish or Protect, although both are very good moves to consider.