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