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