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)(16,24)(21,28)(23,26)(25,27)(5,6)(7,10)(8,9)(11,12)(13,14)(15,20)(16,25)(17,19)(18,22)(21,23)(24,27)(26,28) involution — undirected(1,2,3,4)(6,9)(10,11)(14,19)(15,17)(20,22)(21,25)(23,26)(27,28)(5,7,8,12)(6,10,9,11)(13,15,18,17)(14,20,22,19)(16,23,24,26)(21,27,28,25)(13,16,18,24)(14,21,22,28)(15,23,17,26)(19,25,20,27)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.