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