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