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