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