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