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)(27,35,38,32)(28,29,34,33)(36,39,37,40)(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)(26,32)(28,37)(29,39)(30,38)(31,35)(33,40)(34,36)(1,4,5,3)(2,6,7,8)(26,31)(27,35)(28,34)(32,38)(36,39)(37,40)(9,12,13,21)(10,15,16,20)(11,18,19,24)(14,22,17,23)(25,28,30,34)(26,33,31,29)(27,36,38,37)(32,39,35,40)(11,19)(14,17)(18,24)(22,23)(25,29,30,33)(26,34,31,28)(27,37,38,36)(32,39,35,40)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.