I'm fairly sure that this is supposed to be Maya cosplaying as Takao, based on hair style, hair ornament, and eye colour. Tagging it as such. The tweet with the image also mentions Maya:

摩耶さま改二まだっすかねー

Which translates to...

Is it time for Maya's Kai Ni upgrade yet?

https://twitter.com/6thbody/status/499560915759403008/photo/1

You know I would love for Maya to get this getup in her Kai Ni.

It's just another variation of the Takao class uniform.
The neck design and tie is different from Takao and she doesn't wear garter belt.