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)(15,21)(16,26)(17,19)(18,25)(20,22)(23,27)(24,28) involution — undirected(5,6)(7,10)(8,9)(11,12)(13,15,22,28,17,23,16,25)(14,18,26,27,19,24,20,21)(2,4)(6,9)(10,12)(15,23)(18,24)(21,27)(25,28) involution — undirected(6,9)(10,12)(13,14)(15,24)(16,20)(17,19)(18,23)(21,28)(22,26)(25,27) involution — undirected(5,7,8,11)(6,10,9,12)(14,19)(18,24)(20,26)(21,27)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.