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