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