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