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