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)(16,20)(17,19)(18,25)(21,26)(23,24)(27,28) involution — undirected(1,2)(3,4)(6,10)(11,12)(13,14,16,20)(15,23,24,22)(17,19,26,21)(18,25,28,27)(13,15)(14,18)(16,24)(17,27)(19,22)(20,28)(21,23)(25,26) involution — undirected(2,4)(5,7,9,8)(6,11,10,12)(14,19)(17,26)(18,22)(20,21)(23,28)(25,27)(5,8,9,7)(6,11,10,12)(14,20)(15,24)(19,21)(25,27)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.