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