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