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