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