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