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