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