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