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