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