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)(14,20)(15,25)(17,19)(21,28)(22,27)(23,24) involution — undirected(2,4)(13,14,18,24)(15,22,25,28)(16,21,26,27)(17,23,19,20)(6,9)(10,12)(13,15)(14,21)(16,17)(18,25)(19,26)(20,22)(23,28)(24,27) involution — undirected(13,16,18,26)(14,22,24,28)(15,17,25,19)(20,27,23,21)(5,7,8,11)(6,10,9,12)(13,17,18,19)(14,23,24,20)(15,16,25,26)(21,28,27,22)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.