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