Terry recently called time on his playing days at the club before making a move down to the Championship with Aston Villa, leaving fellow centre-back Cahill to step into the skipper's role at Stamford Bridge.
"This choice was a natural choice because Gary has played for the club for many years and has won a lot," Conte told reporters ahead of the new season.
"It is right to make this decision. I am happy for this."
Chelsea begin the defence of their Premier League crown when they visit Burnley on Saturday afternoon.