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