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