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