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