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