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