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