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