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)(11,17,19,14)(12,15)(13,16)(18,23,24,21)(20,22)(25,26)(27,33,35,40)(28,32)(29,31)(30,34,38,36)(37,39)(2,5)(3,7)(9,11)(10,14)(12,18)(13,19)(15,21)(16,17)(20,24)(22,23)(25,27,29,35)(26,30,31,38)(28,36,37,34)(32,40,39,33)(9,12)(10,15)(11,18)(13,20)(14,21)(16,22)(17,23)(19,24)(26,31)(30,38)(32,39)(33,40) involution — undirected(12,20)(15,22)(18,24)(21,23) 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.