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