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