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