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