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