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