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