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