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