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