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