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