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