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