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