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