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