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)(15,17)(16,24)(18,22)(19,21)(20,25)(23,26)(27,28) involution — undirected(1,2)(3,4)(6,9)(10,11)(13,15,18,21,19,22,17,14)(16,24,27,20,26,23,25,28)(2,4)(13,16)(14,20)(15,23)(17,25)(18,27)(19,26)(21,28)(22,24) involution — undirected(5,7,8,12)(6,10,9,11)(14,21)(15,22)(20,28)(23,24)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.