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