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