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