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