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