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