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