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