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