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