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