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