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