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