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