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