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