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