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)(27,35)(28,33)(29,38)(30,39)(31,34)(32,37)(36,40)(2,6)(5,8)(25,27,31,29)(26,32,34,40)(28,37,30,36)(33,38,39,35)(9,12,14,13)(10,16,17,21)(11,19,20,22)(15,23,18,24)(25,28,31,30)(26,33,34,39)(27,36,29,37)(32,35,40,38)(9,13,14,12)(10,16,17,21)(11,19,20,22)(15,24,18,23)(25,29,31,27)(26,32,34,40)(28,36,30,37)(33,38,39,35)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.