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