One vertex per element, one color per generator, with an edge from x to x·s.
(5,6)(7,9)(8,10)(11,12)(14,20)(15,23)(16,26)(17,19)(21,27)(24,25) involution — undirected(1,2)(3,4)(5,7,9,6)(8,11,12,10)(13,14)(15,21)(16,25)(17,28)(18,20)(19,22)(23,26)(24,27)(2,4)(5,8,9,12)(6,10,7,11)(13,15,18,25)(14,21,20,16)(17,23,19,24)(22,27,28,26)(6,7)(10,11)(13,16)(14,15)(17,27)(18,21)(19,26)(20,25)(22,24)(23,28) involution — undirected(13,17,18,19)(14,22,20,28)(15,24,25,23)(16,27,21,26)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.