One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,5)(4,6)(7,8)(11,15)(13,16)(17,18,21,23)(19,20,22,24)(25,26)(27,30)(28,33)(29,34)(31,36)(32,38)(35,39)(37,40)(1,2,4,6)(3,5,8,7)(17,19)(18,20)(21,22)(23,24)(26,27)(31,33)(32,34)(39,40)(1,2)(3,7)(4,6)(5,8)(9,10,12,14)(11,13,15,16)(17,20)(18,22)(19,23)(21,24)(25,27,30,26)(28,33,36,31)(29,32,38,34)(35,39,37,40)(1,2)(3,7)(4,6)(5,8)(9,11,12,15)(10,13,14,16)(25,28)(26,31)(27,33)(29,37)(30,36)(32,40)(34,39)(35,38)(1,3,4,8)(2,5,6,7)(25,29,30,38)(26,32,27,34)(28,35,36,37)(31,39,33,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.