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