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)(19,20,22,23)(25,26)(27,30)(28,31)(29,37)(32,36)(33,38)(34,40)(35,39)(1,3,4,8)(2,5,6,7)(9,11,15,21)(10,16,18,24)(12,22,17,19)(13,23,14,20)(25,27)(26,30)(28,35)(29,33)(31,39)(32,40)(34,36)(37,38)(9,12,14,10,15,17,13,18)(11,19,20,24,21,22,23,16)(26,31)(27,33,35,34)(30,38,39,40)(32,37)(2,6)(5,7)(9,13,15,14)(10,17,18,12)(11,20,21,23)(16,22,24,19)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.