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