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