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