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