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