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