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