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