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