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