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