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