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