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