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