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