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