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