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)(25,26,30,33)(27,36,34,29)(28,32,37,40)(31,35,38,39)(9,11,14,20)(10,15,17,18)(12,19,13,22)(16,23,21,24)(25,27)(26,29)(28,31)(30,34)(32,39)(33,36)(35,40)(37,38)(2,5)(6,8)(25,28,38,34,30,37,31,27)(26,32,39,29,33,40,35,36)(1,3,4,7)(2,6,5,8)(9,12,14,13)(10,16,17,21)(11,19,20,22)(15,23,18,24)(26,33)(29,36)(32,40)(35,39)(9,13,14,12)(10,16,17,21)(11,19,20,22)(15,24,18,23)(25,29,38,40,30,36,31,32)(26,34,39,37,33,27,35,28)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.