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