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