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