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)(27,31)(28,35)(29,32)(30,33)(34,39)(36,40)(37,38) involution — undirected(3,7)(6,8)(10,15)(12,16)(18,21)(20,22)(25,27,30,28)(26,31,33,35)(29,34,38,36)(32,39,37,40)(1,2)(3,6)(4,5)(7,8)(10,15)(11,17)(18,21)(19,24)(27,28)(31,35)(34,36)(39,40) involution — undirected(9,11)(10,16)(12,15)(13,19)(14,17)(18,22)(20,21)(23,24)(25,28,30,27)(26,31,33,35)(29,36,38,34)(32,39,37,40)(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)(27,31)(28,35)(29,37)(30,33)(32,38)(34,40)(36,39)(1,2)(3,6)(4,5)(7,8)(9,13,14,23)(10,18,15,21)(11,19,17,24)(12,20,16,22)(25,29,30,38)(26,32,33,37)(27,34,28,36)(31,39,35,40)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.