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