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