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