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