One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,4)(3,7,8,6)(9,10,13,16)(11,14,18,22)(12,15,20,24)(17,21,19,23)(25,26,32,38)(27,33,41,50)(28,42,29,35)(30,37,31,36)(34,45,52,44)(39,48,43,56)(40,53,46,49)(47,54,51,55)(1,3)(2,6)(4,7)(5,8)(9,11)(10,14)(12,19)(13,18)(15,23)(16,22)(17,20)(21,24)(25,27,32,41)(26,33,38,50)(28,43,29,39)(30,46,31,40)(34,51,52,47)(35,48,42,56)(36,53,37,49)(44,54,45,55)(9,12)(10,15)(11,17)(13,20)(14,21)(16,24)(18,19)(22,23)(25,28,32,29)(26,34,38,52)(27,39,41,43)(30,44,31,45)(33,47,50,51)(35,36,42,37)(40,54,46,55)(48,49,56,53)(3,8)(6,7)(12,20)(15,24)(17,19)(21,23)(25,29,32,28)(26,35,38,42)(27,39,41,43)(30,44,31,45)(33,48,50,56)(34,36,52,37)(40,55,46,54)(47,49,51,53)(1,4,5,2)(3,7,8,6)(10,16)(11,18)(15,24)(17,19)(25,30,32,31)(26,36,38,37)(27,40,41,46)(28,44,29,45)(33,49,50,53)(34,42,52,35)(39,54,43,55)(47,56,51,48)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.