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