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