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