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