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