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