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