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