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