Marco van Ginkel and Germany international Andre Schurrle have moved to Stamford Bridge this summer along with Mark Schwarzer and there is speculation that Wayne Rooney could yet join them after Mourinho admitted his admiration for the England striker.
Cahill told Sky Sports News: "We all know about Wayne and how good a player he is. He's world class. I'm sure he'll sort out what he's doing in the near future."
As for the new manager, Cahill added: "A lot of players at Chelsea now haven't worked under Jose Mourinho and there's only a handful who have, so it's new for the players and the manager.
"It's going to be similar for all the clubs that have changed their manager, getting to know the players. These pre-season trips are ideal for that.
"Transfer windows is just players coming and going. Sometimes it's better when the window shuts and it settles down and you know what squad you've got.
"You don't know whether things are true or not. We've just got to get on with our job and get ourselves fit and get prepared for the start of the season."
Meanwhile, Kevin De Bruyne has admitted he would not be happy if he was loaned out again this season and he is ready to fight for a first-team place.
The Belgium midfielder spent last season at Werder Bremen and is yet to play for the club since he was signed for £7million 18 months ago.
"The manager called me back and said that I have to stay," he said. "If he gives me chances, then I have to prove myself on tbe pitch.
"I can talk all I want but if I don't show myself on the pitch, I will not get a lot of chances, that's for sure. I'm confident in myself and I'm ready to fight for my spot."