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