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