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