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