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