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