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