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