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