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