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