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