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