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)(14,15)(18,22)(20,24)(25,26,29,32)(27,30,33,37)(28,35,36,31)(34,40,39,38)(1,2,4,6)(3,5,7,8)(9,10,12,13)(11,15,16,14)(17,18,21,22)(19,20,23,24)(27,33)(30,37)(34,39)(38,40)(3,7)(5,8)(9,11,12,16)(10,14,13,15)(17,19,21,23)(18,20,22,24)(25,26)(27,30)(28,31)(29,32)(33,37)(34,38)(35,36)(39,40)(1,2)(3,8)(4,6)(5,7)(9,10)(11,14)(12,13)(15,16)(17,20,21,24)(18,19,22,23)(25,27)(26,30)(28,34)(29,33)(31,38)(32,37)(35,40)(36,39)(1,3)(2,5)(4,7)(6,8)(9,11)(10,15)(12,16)(13,14)(17,19)(18,20)(21,23)(22,24)(25,28,29,36)(26,31,32,35)(27,34,33,39)(30,38,37,40)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.