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)(25,26,31,35)(27,32,36,39)(28,38,37,40)(29,34,30,33)(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)(28,29)(30,37)(31,36)(33,40)(34,38)(35,39)(9,12,14,22,15,23,13,21)(10,16,17,20,11,18,19,24)(25,28,29,27,31,37,30,36)(26,32,33,38,35,39,34,40)(1,4,5,3)(2,7,8,6)(9,13,15,14)(10,17,11,19)(12,21,23,22)(16,20,18,24)(27,36)(28,37)(32,39)(38,40)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.