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