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