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