Cahill rejoined the south London side in February in an attempt to get game time ahead of the World Cup, before retiring from internationals after Australia's exit from the tournament.
He has had an illustrious career, most famous for an eight year stint with Everton as well as time spent at New York Red Bulls and Melbourne City.
"I want to help grow the game in India and encourage young kids to play football," said Cahill.
"To be a part of their project is massive for me because I know I can help the team on and off the park with my leadership and experience."