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