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