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