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