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