Assuming that I am reading it correctly, the CMOC manual states that without switches CMOC creates CoCo RS-DOS executables. In which case I guess the switches for Bin2Cas should be:
Edit. Whilst I was reading the CMOC manual and Bin2Cas help file Bosco answered the query! Personally I would follow Bosco's advice since he has experience of the programs.
I'm not familiar with C or CMOC but maybe other users on this forum can help you further?
Failing that, maybe try contacting CMOC's author? He's written a number of sample programs, including graphical card games, (which you'll find the source for on his website).
The only ways I can really think of drawing graphics would be either writing asm to d ogrpahics inline with my C programs or somehow using them alongside BASIC, both I don't really want to do. The demos on the site look interesting but seem to rely on tandy colour basic being used(?)