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