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