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