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)(25,26,31,30)(27,34,29,32)(28,36,38,33)(35,39,37,40)(1,2)(3,6)(4,7)(5,8)(10,15)(12,23)(16,19)(18,21)(25,27,31,29)(26,32,30,34)(28,35,38,37)(33,39,36,40)(1,3)(2,5)(4,8)(6,7)(10,15)(11,20)(17,22)(18,21) involution — undirected(9,11)(10,16)(12,21)(13,22)(14,20)(15,19)(17,24)(18,23)(25,28)(26,33)(27,35)(29,37)(30,36)(31,38)(32,39)(34,40) involution — undirected(1,3)(2,6)(4,8)(5,7)(9,12)(10,17)(11,21)(13,19)(14,23)(15,22)(16,24)(18,20)(25,29,31,27)(26,32,30,34)(28,37,38,35)(33,39,36,40)(1,2)(3,5)(4,7)(6,8)(9,13,14,24)(10,18,15,21)(11,22,20,17)(12,16,23,19)(25,30,31,26)(27,34,29,32)(28,36,38,33)(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.