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