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