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)(11,13)(12,18)(14,16)(15,17)(19,22)(20,23)(21,24)(27,34)(32,35)(36,39)(37,40) involution — undirected(1,3,6,7)(2,4,5,8)(9,11,15,14)(10,16,17,13)(12,20,21,19)(18,22,24,23)(25,26,30,31)(27,35,34,32)(28,29,33,38)(36,40,39,37)(1,4,6,8)(2,7,5,3)(10,17)(12,21)(13,16)(19,20)(26,31)(28,33)(32,35)(36,39)(1,2,6,5)(3,8,7,4)(9,12,15,21)(10,18,17,24)(11,19,14,20)(13,22,16,23)(25,27,30,34)(26,32,31,35)(28,36,33,39)(29,37,38,40)(1,4)(2,3)(5,7)(6,8)(9,13,15,16)(10,11,17,14)(12,22,21,23)(18,19,24,20)(25,28)(26,29)(27,36)(30,33)(31,38)(32,37)(34,39)(35,40)(1,5,6,2)(3,8,7,4)(9,14,15,11)(10,13,17,16)(12,20,21,19)(18,22,24,23)(25,29)(26,33)(27,37)(28,31)(30,38)(32,39)(34,40)(35,36)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.