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