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