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