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