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)(11,18,21,23)(12,16,13,22)(15,20,24,19)(25,26,30,29)(27,31,34,37)(28,32,36,35)(33,39,40,38)(9,11,14,21)(10,15,17,24)(12,19,13,20)(16,23,22,18)(25,27,30,34)(26,31,29,37)(28,33,36,40)(32,38,35,39)(2,5)(3,8)(6,7)(9,12,14,13)(10,16,17,22)(11,19,21,20)(15,23,24,18)(25,28)(26,32)(27,33)(29,35)(30,36)(31,38)(34,40)(37,39)(2,6)(5,7)(9,12,14,13)(10,16,17,22)(11,20,21,19)(15,18,24,23)(25,29,30,26)(27,31,34,37)(28,35,36,32)(33,38,40,39)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.