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