While not specificly Co.G. these are items held at the Lincoln library in Springfield on the 41 IL.The date of the formation and the fact the original muster was Capt. Longs Il.Guards might indicate a home guard which hadn't been issued regulation uniforms.I assume you have sought out local historians say in Taylorville.I too tried to find his grave to no avail..The Jackson MS. cemetery specificly states about the numbers of unknown soldiers buried there.There are several that are good at uniform identification on the Arms and Equipt site within history-sites family of sites.

http://www.illinoiscivilwar150.org/dev/pdfs/JIH-CWB1.pdf