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