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)(15,17)(16,18)(19,20) involution — undirected(6,10)(8,12)(13,15)(14,19)(16,17)(18,20)(21,22,24,26)(23,25,27,28)(1,2,3,4)(6,10)(7,11)(14,16)(15,20)(21,22)(23,25)(24,26)(27,28)(5,7)(6,8)(9,11)(10,12)(13,16,18,14)(15,17,20,19)(21,23,24,27)(22,25,26,28)(5,8)(6,7)(9,12)(10,11)(13,17)(14,15)(16,20)(18,19) 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.