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)(28,35)(31,36)(32,37)(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)(9,11)(10,14)(12,19)(13,18)(15,22)(16,17)(20,24)(21,23)(25,26,28,30,29,32,35,37)(27,31,34,36,33,38,39,40)(1,3,4,7)(2,6,5,8)(11,18)(14,17)(19,24)(22,23)(25,27,29,33)(26,31,32,38)(28,34,35,39)(30,36,37,40)(9,12,13,20)(10,15,16,21)(11,19,18,24)(14,22,17,23)(26,32)(27,33)(30,37)(34,39)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.