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