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