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