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