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