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