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