Quoted By:
I really think it's going to be a dragon type, because of the colors.
Even without the special thing, I think it'd be dragon because of the colors. Every other eevelution looks the color of the typing, and Sylveon isn't green or grey and light blue, so I doubt it's gonna be bug or flying.
Now, if it were to be a new typing (here's hoping for the new LOVE type), it'd be awesome, but I don't think GF is going to introduce a new typing.