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