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