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