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)(11,19)(12,16)(13,26,27,17)(14,18)(15,22)(20,30)(21,33,35,29)(23,28)(24,31,37,38)(25,32)(34,39,36,40)(1,3,5,8)(2,6,4,7)(9,11)(10,15,18,19)(12,23,25,20)(13,21,27,35)(14,22)(16,30)(17,29)(24,36)(26,33)(28,32)(31,40,38,39)(34,37)(1,2,5,4)(3,6,8,7)(9,12,14,25)(10,16,18,32)(11,20,22,23)(13,24,27,37)(15,28,19,30)(17,31,26,38)(21,34,35,36)(29,39,33,40)(1,4,5,2)(3,6,8,7)(9,13)(10,17)(11,21,22,35)(12,24)(14,27)(15,29,19,33)(16,31)(18,26)(20,34,23,36)(25,37)(28,39,30,40)(32,38)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.