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