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