The Dutchman took over at Stamford Bridge in December after the dismissal of Jose Mourinho.
And Mikel told BBC's Match of the Day that the mood at Chelsea is now better.
"It's the way he communicates with the players and maybe that's what the players felt they didn't get from the previous manager," he said.
"Sometimes players - not just because they're not playing - you need to communicate with them. You need to speak to them and don't just ignore them because players like to be communicated to.
"This is what [Hiddink] has brought into the football club. In some ways you barely know he is in there, he is that calm and relaxed."
Hiddink, who led Chelsea to FA Cup triumph in 2009, took over with the Blues 16th in the Premier League, one point above the relegation zone. They are currently 13th, nine points off the final Champions League place.
The Nigerian was linked with a move away from the club last summer but Mourinho reportedly refused to sanction his departure. However, he has become a regular under Hiddink.
Chelsea midfielder John Mikel Obi says communication has improved within the team since the arrival of interim manager Guus Hiddink.