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