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