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