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