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