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