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