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