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