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