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