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