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