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