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