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