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