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