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