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