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