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