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