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