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