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