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