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