Taken from Acts 19 :
2 He said unto them, Have ye received the Holy Ghost since ye believed? And they said unto him, We have not so much as heard whether there be any Holy Ghost.
3 And he said unto them, Unto what then were ye baptized? And they said, Unto John's baptism.
4 Then said Paul, John verily baptized with the baptism of repentance, saying unto the people, that they should believe on him which should come after him, that is, on Christ Jesus.
Edit: It's pretty clear it's Christ's baptism. "Christ's Baptism" doesn't mean that you become baptised into Christ's name, but you get baptised according to how Christ said you should be baptised. And how did Christ put it?
...baptizing them in the name of the Father and of the Son and of the Holy Spirit...
Thus, I would say, each time when baptizing, baptise in the names of the Three Beings of the Trinity:
I baptize you in the name of the Father, and of the Son, and of the Holy Spirit