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