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