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