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