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