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