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