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