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