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