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