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