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