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