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