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