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