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