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