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