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