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