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