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)(13,14,18,20)(15,16,19,17)(5,7)(6,9)(8,12)(10,11)(13,15,18,19)(14,16,20,17)(22,25)(26,28)(5,7,8,12)(6,9,11,10)(13,16,18,17)(14,15,20,19)(21,22,24,25)(23,26,27,28)(1,2)(3,4)(5,7)(6,10)(8,12)(9,11)(13,14)(15,16)(17,19)(18,20) involution — undirected(5,6)(7,9)(8,11)(10,12)(13,17,18,16)(14,19,20,15)(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.