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