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