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