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