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