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