One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,4)(3,7,8,6)(9,10,13,16)(11,21,24,33)(12,18,27,31)(14,20,15,19)(17,22,30,25)(23,39,26,37)(28,36,29,35)(32,40,34,38)(1,3,5,8)(2,6,4,7)(10,16)(11,22)(14,15)(17,21)(18,31)(23,38)(24,25)(26,40)(28,29)(30,33)(32,37)(34,39)(2,4)(6,7)(9,11)(10,17)(12,26)(13,24)(14,22)(15,25)(16,30)(18,34)(19,33)(20,21)(23,27)(28,38)(29,40)(31,32)(35,39)(36,37) involution — undirected(1,4,5,2)(3,7,8,6)(9,12,13,27)(10,18,16,31)(11,23,24,26)(14,29,15,28)(17,32,30,34)(19,36,20,35)(21,37,33,39)(22,38,25,40)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.