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