One vertex per element, one color per generator, with an edge from x to x·s.
(5,6)(7,12)(8,10)(9,11)(13,14)(15,22)(16,20)(17,26)(18,23)(19,24)(21,25)(27,28) involution — undirected(1,2)(3,4)(5,7,9,8)(6,10,11,12)(13,15,16,23)(14,18,20,22)(17,24,25,27)(19,26,28,21)(2,4)(13,15)(14,19)(16,23)(17,27)(18,21)(20,28)(22,26)(24,25) involution — undirected(1,2)(3,4)(5,8,9,7)(6,10,11,12)(15,23)(18,22)(19,28)(24,27)(2,4)(15,23)(18,22)(19,28)(24,27) involution — undirectedA 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.