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