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