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