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