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