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