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)(13,14,17,18)(15,20,19,16)(22,26)(23,28)(6,9)(10,11)(13,14)(15,20)(16,19)(17,18)(22,26)(23,28) involution — undirected(6,9)(10,11)(14,18)(15,19)(21,22,25,26)(23,27,28,24)(1,2,3,4)(5,6)(7,10)(8,9)(11,12)(13,15,17,19)(14,16,18,20)(21,23)(22,27)(24,26)(25,28)(5,7)(6,10)(8,12)(9,11)(13,16)(14,19)(15,18)(17,20)(21,24,25,27)(22,23,26,28)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.