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