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