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