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