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