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