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