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