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