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