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