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