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