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