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