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