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