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