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