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