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