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