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