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