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