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