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