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