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