One vertex per element, one color per generator, with an edge from x to x·s.
(3,7)(6,8)(10,12)(11,15)(18,22)(20,24)(25,26,29,32)(27,33,35,30)(28,36,38,31)(34,39,37,40)(11,15)(14,16)(18,22)(19,23)(25,27,29,35)(26,30,32,33)(28,34,38,37)(31,39,36,40)(1,2,5,4)(3,6,7,8)(9,10,13,12)(11,14,15,16)(17,18)(19,20)(21,22)(23,24)(25,27)(26,30)(28,37)(29,35)(31,40)(32,33)(34,38)(36,39)(1,3)(2,6)(4,8)(5,7)(9,11,13,15)(10,14,12,16)(17,19)(18,20)(21,23)(22,24)(25,26)(27,30)(28,36)(29,32)(31,38)(33,35)(34,40)(37,39)(1,4,5,2)(3,8,7,6)(9,12,13,10)(11,16,15,14)(17,20)(18,19)(21,24)(22,23)(25,28,29,38)(26,31,32,36)(27,34,35,37)(30,39,33,40)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.