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