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