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