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