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