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