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