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