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