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