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