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