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