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) involution — undirected(1,2)(3,4)(5,7,9,8)(6,10,12,11)(13,14,18,19)(15,23,25,28)(16,22,17,21)(20,26,27,24)(2,4)(14,19)(20,27)(21,22)(23,28) involution — undirected(2,4)(5,7,9,8)(6,11,12,10)(13,15)(14,20)(16,24)(17,26)(18,25)(19,27)(21,23)(22,28)(5,8,9,7)(6,11,12,10)(13,16,18,17)(14,21,19,22)(15,24,25,26)(20,23,27,28)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.