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)(11,13)(12,14)(15,16)(18,20)(19,23)(25,26,30,27)(28,31,35,33)(29,34,37,32)(36,39,40,38)(9,11,12,15)(10,13,14,16)(18,20)(22,24)(26,27)(28,35)(32,34)(36,40)(9,10,12,14)(11,13,15,16)(17,18,21,20)(19,24,23,22)(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)(11,13)(12,14)(15,16)(17,19,21,23)(18,22,20,24)(25,28,30,35)(26,31,27,33)(29,36,37,40)(32,38,34,39)(1,3,4,7)(2,5,6,8)(9,11)(10,13)(12,15)(14,16)(17,20,21,18)(19,24,23,22)(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.