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)(15,22)(16,20)(17,25)(18,21)(19,23)(24,27)(26,28) involution — undirected(2,3)(5,7,10,6)(8,12,9,11)(1,2,4,3)(13,15)(14,19)(16,23)(17,26)(18,24)(20,27)(21,28)(22,25)(5,8,10,9)(6,11,7,12)(13,16,18,17)(14,20,21,25)(15,23,24,26)(19,27,28,22)(1,3,4,2)(5,9,10,8)(6,11,7,12)(14,21)(19,28)(20,25)(22,27)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.