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