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