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