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