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