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