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