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