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