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