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