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