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