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