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