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