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