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