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