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