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