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