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