I would pick return, because, unless you've treated it horribly recently, it's Friendship should be extremely high, because you have to have high friendship to evolve it to Togetic.
Since return's power is based on Friendship, and yours is extremely high most likely, it'll most likely do more than Extreme Speed, also it has more PP than ESpeed, meaning you'll be able to use it more for the same amount of accuracy. 220 is the min for a Togetic evolution, and since you evolved it you probably have used it more, making it higher than that, so using the damage: Return, at 220, would be 88 damage, meaning it would do more than Espeed, which is 80, unless you treated it really badly after evolving it. Also, they use the same type of damage, Physical, so no worry there.
Also, according to this
Togekiss has base 50 Attack so in a generic case, no Extremespeed is practically useless since the most your going to do with it is finish of a Pokemon on like 5-10% health
So you're not gonna do much damage anyway. The only reason I would pick Espeed is if you really, really need a priority move. But you should still go with Return, since, as PK mentioned, you should have high speed if you use this Togekiss a lot and are higher level than most wild Pokemon.
So, final answer:Pick Return, it fits Togekiss a whole lot better
Sources:Togekiss line info, Return page, Extreme Speed page, and this https://pokemondb.net/pokebase/149566/is-extremespeed-for-togekiss-worth-it.