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