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