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