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