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