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