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