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