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