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