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