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