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