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