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