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