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