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