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