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