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