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