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