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