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)(11,15,12,20)(13,22,23,17)(16,19,24,21)(25,26,30,33,29,32,39,28)(27,34,37,38,35,31,40,36)(1,3,5,4)(2,6,7,8)(9,11,14,12)(10,15,18,20)(13,19,23,21)(16,22,24,17)(25,27,29,35)(26,31,32,34)(28,38,33,36)(30,37,39,40)(9,12,14,11)(10,16,18,24)(13,19,23,21)(15,22,20,17)(27,35)(31,34)(36,38)(37,40)(1,4,5,3)(2,6,7,8)(11,12)(15,20)(16,24)(19,21)(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.