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