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