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