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