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