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