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