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