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