Cahill was given a straight red following a late tackle from behind on Scott Parker in the early stages of Bolton's 3-0 defeat at Tottenham. Referee Stuart Attwell decided that Cahill denied Parker a clear goal-scoring opportunity despite the fact that the defender hauled down the 31-year-old 40 yards from goal when Bolton had plenty of cover.
Coyle said: "I will be appealing the decision as soon as I can. It was baffling, bemusing."
The Bolton boss has seen five of his players sent off so far this season and thinks a number of decisions have gone against him since he took over at the Reebok Stadium in January 2010.
The 45-year-old continued by suggesting that Riley, the man who monitors refereeing standards for the Professional Game Match Officials Board, has not taken his remonstrations seriously.
Coyle said: "I spoke to him after we lost to an offside goal in the 94th minute at Liverpool. He said he'd ring me back.
"I rang him after we played at White Hart Lane, Spurs got two penalties and we had the biggest shout when Cahill was brought down, but was booked for diving. I rang him three or four days later after he was supposed to ring me back, so you can draw your own conclusions on that. Mike's obviously in charge of those refs."
When asked if he felt his side were not getting the rub of the green with refereeing decisions because they are not one of the division's top clubs, the Scot replied: "There's a lot of merit in the question."
Source: PA
Source: PA