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