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