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