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