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