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