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