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