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