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