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