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