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