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)(11,15)(12,16)(13,14)(17,20)(18,22)(19,21)(23,24)(25,26)(27,38)(28,35)(29,45)(30,36)(31,37)(32,47)(33,42)(34,44)(39,53)(40,49)(41,54)(43,50)(46,52)(48,56)(51,55) involution — undirected(3,7)(5,8)(10,14)(15,20)(16,21)(22,24)(25,27,31,42)(26,33,37,38)(28,40,29,39)(30,41,32,43)(34,51,52,48)(35,53,45,49)(36,50,47,54)(44,56,46,55)(1,3)(2,5)(4,7)(6,8)(9,11)(10,15)(12,18)(13,17)(14,20)(16,22)(19,23)(21,24)(25,28,31,29)(26,34,37,52)(27,39,42,40)(30,44,32,46)(33,48,38,51)(35,36,45,47)(41,55,43,56)(49,50,53,54)(2,6)(3,7)(11,17)(15,20)(18,23)(22,24)(25,29,31,28)(26,35,37,45)(27,40,42,39)(30,44,32,46)(33,49,38,53)(34,36,52,47)(41,55,43,56)(48,50,51,54)(9,12,13,19)(10,16,14,21)(11,18,17,23)(15,22,20,24)(25,30,31,32)(26,36,37,47)(27,41,42,43)(28,44,29,46)(33,50,38,54)(34,45,52,35)(39,55,40,56)(48,53,51,49)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.