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