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