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