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