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