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