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